This section provides background information related to the present disclosure, which is not necessarily prior art.
In an effort to reduce fossil fuel emissions and other pollutants emitted from automobiles that use internal combustion engines, hybrid electric automobiles (HEV) and electric automobiles (EV) have been designed and implemented to mitigate the environmental effects of the internal combustion engine. In order to provide power to these battery systems, the HEVs and EVs may be provided with power by connecting to the electrical grid. The battery system of an HEV or EV may be connected to the electrical grid by using a copper cable. Typically, the copper cable will have one end that has a plug, thus allowing the battery system to connect to the electrical grid.
The battery system of an HEV or EV may also connect to the electrical grid by implementing a wireless or contactless charging system. A wireless charging system, which may also be referred to as a wireless power transfer (WPT) system, may utilize the mutual inductance between two inductive coils to provide power to the battery system of the HEV or EV. The electrical grid may induce a voltage at a first coil, and as a result of the inductive coupling between the first coil and a second coil connected to the battery system of the HEV or EV, the second coil will induce a voltage and subsequently charge the battery system of the HEV or EV.
While the wireless charging system has the advantage of not requiring cables, connectors, and plugs, the wireless charging system often has low power efficiency. The efficiency of wireless charging systems may be affected by a coil misalignment between the transmitting coils and the receiving coils. For example, the receiving coil may be misaligned with the transmitting coil. A misalignment may increase the distance between the two coils, and consequently, decrease the mutual inductance between the coils. A decrease in mutual inductance reduces the overall power efficiency of the WPT system.